1. Field of the Invention
This invention relates to instrumentation and computing systems and, more particularly, to synchronizing devices in instrumentation and/or computing systems.
2. Description of the Related Art
Time-triggered control is often used to synchronize real-time computing systems. In a time-triggered system, all activities are carried out at certain predesignated points in time. To achieve this, nodes in time-triggered systems have a common notion of time, typically through the use of synchronized clocks in each node.
One type of system that may be controlled according to a time-triggered or event-triggered control system is an instrumentation system. An instrument is a device that collects data or information from an environment or unit under test (UUT) and displays this information to a user. An instrument may also analyze and process acquired data prior to displaying the data to the user. Some instruments may be used to provide test stimuli to a UUT. Examples of instruments include oscilloscopes, digital multimeters, pressure sensors, arbitrary waveform generators, digital waveform generators, etc. The information that may be collected by respective instruments includes information describing voltage, resistance, distance, velocity, pressure, frequency of oscillation, humidity, or temperature, among others.
Computer-based instrumentation systems typically include transducers for transducing a physical phenomenon into an electrical signal, signal conditioning logic to perform amplification, isolation, and/or filtering, and analog-to-digital (A/D) conversion logic for receiving analog signals and providing corresponding digital signals to the host computer system.
In a computer-based system, the instrumentation hardware or device is typically an expansion board plugged into one of the I/O slots of the computer system. In another common instrumentation system configuration, the instrumentation hardware is coupled to the computer system via other means such as through a VXI (VME eXtensions for Instrumentation) bus, a PXI (PCI eXtensions for Instrumentation) bus, a GPIB (General Purpose Interface Bus), a serial port or bus, or parallel port of the computer system. The instrumentation hardware may include a DAQ board, a computer-based instrument such as a multimeter, or another type of instrumentation device.
Modern instrumentation systems may also include networked measurement systems. In a networked measurement system, two or more instrumentation or measurement devices may be coupled over a network and may operate together to perform a instrumentation or measurement function.
Some computer-based and/or network-based instrumentation systems include several instrumentation and/or DAQ devices. Each device may generate and/or capture data. Other resources within the system may process captured data. In order to synchronize devices within an instrumentation system so that data may be accurately generated, captured, and/or processed, it may be desirable to use a time-triggered control system to synchronize the instrumentation system devices to a common time. While existing synchronization schemes currently exist, it is desirable to have improved synchronization systems. Such a synchronization scheme may also be desirable in other systems, such as control and monitoring systems.